This invention relates to an apparatus to maintain the water level in a swimming pool at a desired elevation, and more particularly, to such an apparatus which will provide an automatic control of valve means in a water supply line so as to accurately supply make-up quantities of water to the swimming pool to maintain the water level within predetermined limits.
In the usual swimming pool construction, filtered water enters the pool through nozzle assemblies passing through the pool walls; while the main drain returning water to the filtering equipment is at the bottom of the pool. In addition to the main drain it is also necessary to provide an overflow gutter or skimmer system around the periphery of the pool to "skim off" surface water and return it to the filtering unit since this surface water contains most of the contaminants such as bacteria, oil and debris.
An example of a gutter and water supply system for a swimming pool is disclosed in my prior U.S. Pat. No. 3,641,594 wherein a gutter is provided with a removable slotted cover and the water supply conduit is carried within the gutter itself. In order that an overflow system extending about the upper periphery of the pool will function in its intended manner, it is necessary that the water level within the swimming pool should be kept within a narrow range. It is virtually impossible to accurately maintain the desired water level in the swimming pool, particularly when the swimming pool is in use, by manually operating a control valve to supply make-up quantities of water. There is, of course, the danger that the swimming pool may be overfilled which could only be detected after the overflow gutter or skimmer system was completely flooded. An abnormally low water level in the pool will cause a failure to supply sufficient quantities of water from the skimmer system to the filter system.